Optical fiber-based devices are exposed to a variety of environmental conditions, including temperature fluctuations, mechanical vibrations, and shock. Thus, robust methods for ensuring the transmission of the optical field between two optical fibers that can withstand these environmental conditions are crucial for the development of fiber-based systems. Further, because optical fibers can be made using a variety of materials, there is a need to couple light between optical fibers having distinct material properties. Mechanical and fusion splicing are the most used methods for connecting optical signals between dissimilar material optical fibers. Mechanical splicing involves mechanically locking the position of the optical fibers in place with variants, including the use of liquids or soft deformable materials to fill the gap between the fibers. Fusion splicing between fibers involves delivering heat to soften the fibers and induce chemical and mechanical bonding both fiber end faces together.
Conventional mechanical and fusion splicing methods suffer from several disadvantages. Fusion splicing methods suffer from limited applicability, as the degree in dissimilarity between materials has to be small to ensure chemical bonding. Mechanical splicing approaches can be flexible with respect to the fiber material, but they display larger insertion losses, lower power handling, and higher sensitivity to thermal variations and mechanical perturbations than those of joints made using fusion splicing. For highly dissimilar materials, the difference in refractive indexes can limit the practical implementation of fluid or soft based intermediaries for mechanical splices, with many higher index fluids being toxic or not being a suitable material to bridge the refractive index difference without significant losses.
Conventional splicing methods cannot be used to splice dissimilar materials and/or result in unsatisfactory insertion loss. For continuous operation of high power laser, losses at the splice of more than I dB are not a viable for commercial applications. The optical power lost at the splice is converted to heat and requires lots of thermal management for sustained operation. Even a small mismatch of the mode field diameter and numerical aperture between the dissimilar fibers can lead to a temperature rise across the spliced interface. Another disadvantage of conventional splicing methods is the catastrophic failure of the splice due to stress at the interface and large thermo-mechanical differences in the dissimilar materials.
Features and advantages of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, in which like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.